The present application claims priority from U.S. provisional application No. 63/433,093 filed on 12 months 16 of 2022, which is incorporated herein by reference in its entirety for all purposes.
Disclosure of Invention
The present disclosure relates to a process for densifying expanded polyethylene, and articles produced by the process for densifying expanded polyethylene. For example, the method and articles produced by the method include selectively densifying portions of an expanded polyethylene substrate to produce a reserve length (storedlength). This may result in desirable characteristics such as increased bend radius, torsional resistance, durability, and the like.
According to one example ("example 1"), an article includes an expanded polyethylene substrate having a longitudinal length, having a first region and a second region, wherein the first region has a first density and the second region has a second density, the second density being greater than the first density, and wherein the second region is embossed.
According to a further alternative example of example 1 ("example 2"), the expanded polyethylene substrate is at least one of longitudinally or laterally compressed, defining a reserve length along at least a portion of the longitudinal length.
According to a further example of example 1 ("example 3"), the expanded polyethylene substrate is a tubular member.
According to a further another example of example 3 ("example 4"), the second zone is a ring extending around the circumference of the tubular member at a longitudinal position defined along the longitudinal length.
According to a further another example of example 4 ("example 5"), the second zone includes a plurality of rings extending around the circumference of the tubular member at a plurality of longitudinal locations defined along the longitudinal length.
According to a further alternative example of example 1 ("example 6"), the expanded polyethylene substrate is free of adhesive.
According to a further alternative example of example 1 ("example 7"), the expanded polyethylene substrate comprises a plurality of expanded polyethylene layers joined together.
According to one example ("example 8"), a method of forming an article includes optionally providing an expanded polyethylene substrate having a first density, selectively densifying a portion of the expanded polyethylene substrate, forming one or more densified portions of the expanded polyethylene substrate, wherein the expanded polyethylene substrate has one or more undensified portions having the first density, and wherein the one or more densified portions have a second density that is greater than the first density, wherein the one or more densified portions are disposed adjacent to the one or more undensified portions.
According to a further another example of example 8 ("example 9"), the method further comprises forming the expanded polyethylene substrate into a tubular member.
According to a further alternative example of example 9 ("example 10"), selectively densifying a portion of the expanded polyethylene substrate comprises applying heat to an outer surface of the expanded polyethylene substrate.
According to a further another example of example 9 ("example 11"), the method further comprises placing the tubular member on a mandrel.
According to a further another example of example 11 ("example 12"), selectively densifying a portion of the expanded polyethylene substrate comprises applying heat to an inner surface of the expanded polyethylene substrate.
According to a further alternative example of example 12 ("example 13"), selectively densifying a portion of the expanded polyethylene substrate includes selectively heating portions of the mandrel.
According to a further alternative example of example 8 ("example 14"), selectively densifying a portion of the expanded polyethylene substrate comprises applying ultrasonic energy to an outer surface of the expanded polyethylene substrate.
According to a further alternative example of example 8 ("example 15"), selectively densifying a portion of the expanded polyethylene substrate comprises applying ultrasonic energy to an inner surface of the expanded polyethylene substrate.
According to one example ("example 16"), a method of forming an article includes optionally providing an expanded polyethylene substrate having a first density, compressing the expanded polyethylene substrate in a longitudinal and/or lateral direction such that the expanded polyethylene substrate is in a longitudinal and/or lateral compressed state, the expanded polyethylene substrate having the first density, selectively densifying a portion of the expanded polyethylene substrate while in the longitudinal and/or lateral compressed state, forming densified portions of the expanded polyethylene substrate, wherein the densified portions have a second density that is greater than the first density, and releasing the expanded polyethylene substrate from the longitudinal and/or lateral compressed state.
According to a further another example of example 16 ("example 17"), the method further comprises forming the expanded polyethylene substrate into a tubular member.
According to a further alternative example of example 17 ("example 18"), selectively densifying a portion of the expanded polyethylene substrate comprises applying heat to an outer surface of the expanded polyethylene substrate.
According to a further another example of example 17 ("example 19"), the method further comprises placing the tubular member on a mandrel.
According to a further alternative example of example 19 ("example 20"), selectively densifying a portion of the expanded polyethylene substrate comprises applying heat to an inner surface of the expanded polyethylene substrate.
According to a further alternative example of example 20 ("example 21"), selectively densifying a portion of the expanded polyethylene substrate includes selectively heating portions of the mandrel.
According to a further another example ("example 22") of example 16, selectively densifying a portion of the expanded polyethylene substrate includes contacting a portion of the expanded polyethylene substrate with an assembly of about 110 degrees celsius to about 180 degrees celsius.
According to a further alternative example of example 16 ("example 23"), selectively densifying a portion of the expanded polyethylene substrate comprises applying ultrasonic energy to an outer surface of the expanded polyethylene substrate.
According to a further another example ("example 24") of example 16, selectively densifying a portion of the expanded polyethylene substrate includes applying ultrasonic energy to an inner surface of the expanded polyethylene substrate.
The above examples are limited thereto and should not be construed as limiting or otherwise narrowing the scope of any inventive concepts otherwise provided by the present disclosure. While multiple examples are disclosed, other embodiments will be apparent to those skilled in the art from the following detailed description, which shows and describes illustrative examples. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.
Detailed Description
Definitions and terms
The present disclosure is not intended to be interpreted in a limiting manner. For example, terms used in the present application should be construed broadly in the context of what is given to such terms in the art.
For imprecise terms, the terms "about" and "approximately" are used interchangeably to mean that a measurement includes the measurement and also includes any measurement reasonably close to the measurement. As will be appreciated by one of ordinary skill in the relevant art and as will be readily determined, the deviation of a measurement value reasonably close to the measurement value from the measurement value is relatively small. Such deviations may be due to measurement errors, differences in measurement and/or manufacturing equipment calibration, manual errors in readings and/or setup measurements, fine adjustments made to optimize performance and/or structural parameters in view of measurement differences associated with other components, imprecise adjustments and/or operations of objects, particularly in a scene, human or machine, and the like. If it is determined that a person having ordinary skill in the relevant art cannot readily determine the value of such reasonably small differences, the terms "about" and "approximately" are understood to mean plus or minus 10% of the value.
The term "laminate" as used herein refers to a multilayer film, composite, or other material, such as, but not limited to, a polymer, such as, but not limited to, an elastomeric, elastomeric or non-elastomeric material, and combinations thereof.
The term "membrane" as used herein generally refers to one or more of a membrane, composite, or laminate.
The term "polyethylene" (PE) as used herein includes all types of polyethylene including, but not limited to, expanded polyethylene (ePE).
The term "selective densification" as used herein generally refers to densification at a predetermined location on a substrate and includes varying degrees of densification, including partial densification (such that the substrate remains porous, open microstructure after densification), as well as complete densification (wherein the substrate has a closed microstructure). Selective densification may include, but is not limited to, densification through a thickness of the substrate or along a length of the substrate while adjacent regions remain undensified.
Description of the embodiments
Those skilled in the art will appreciate that the various aspects of the disclosure may be implemented by any number of methods and apparatus configured to perform a desired function. It should also be noted that the drawings referred to herein are not necessarily drawn to scale, but are potentially exaggerated to illustrate various aspects of the present disclosure, and should not be considered limiting in this regard.
The apparatus shown in fig. 1 is provided as an example of various features of the apparatus, and although combinations of these illustrated features are clearly within the scope of the invention, this example and its description are not meant to limit the inventive concepts provided herein to only one or more of the features shown in fig. 1 from fewer, additional, or alternative features.
Various forms of expanded polyethylene may be implemented in the articles and methods, including but not limited to films, membranes, tapes, tubing, and the like. It is further understood that the expanded polyethylene may be provided with a variety of properties including different thicknesses, fibril and node structures, voids, densities, and the like. Thus, the embodiments discussed herein are not limited to a particular initial condition or form, but are understood to broadly encompass any expanded polyethylene starting material suitable for use in the process.
Referring to fig. 1, an article 10 is shown, the article 10 comprising an expanded polyethylene substrate 12 having a first region 14 and a second region 16. The first region 14 has a first density and the second region 16 has a second density. The second density of the second region 16 is greater than the first density of the first region 14. In addition, the second region 16 is embossed. The article 10 may be provided in any configuration including, but not limited to, those shown in the figures. The article 10 may be provided in various three-dimensional forms, such as a tubular member or tubular form as shown in fig. 1. The article 10 may also be formed into a two-dimensional form, such as a sheet. The sheet formed from article 10 may be provided in a variety of configurations, such as a circular form, a rectangular form, or any other geometric form. It should be understood that any two-dimensional form may be manipulated to provide a three-dimensional form. For example, the article 10 may be formed by providing a sheet material that is attached (e.g., adhered, bonded, fused, etc.) to itself, thereby forming, for example, a tubular member. Providing the article 10 in various forms may impart specific characteristics to the article 10 that are unique to each form of the article 10 or that are constant regardless of the form of the article 10.
In one embodiment, such as the embodiment shown in fig. 1, the article 10 is formed into a tubular member 100. The tubular member 100 includes first and second regions 14, 16 operable to impart enhanced durability (including wear resistance) when subjected to repeated bending actions, including in embodiments where comfort and durability are important factors. In addition, tubular member 100 exhibits torsional resistance, bending radius, comfort, and reserve length. While these features are discussed specifically with respect to tubular member 100, it should be understood that articles 10 provided in other forms may include these and similar features.
With further reference to fig. 1, the tubular member 100 is provided with first and second regions 14, 16, wherein the second region 16 is a ring 102 that is a densified region positioned (e.g., extending) around the circumference of the tubular member 100. The tubular member 100 may include a plurality of rings 102 as densified regions of the tubular member 100, wherein each ring 102 is spaced apart from an adjacent ring 102 along the longitudinal length of the tubular member 100. Other geometries of the circumferential out-of-ring densification region are also contemplated. For example, the densified regions can be shaped in a spiral pattern along the longitudinal length of the tubular member. The longitudinal length may be along a longitudinal axis of the tubular member 110. The ring 102, which provides the densified region, provides radial support to the tubular member 100, resisting radial forces and collapse from external forces (e.g., mechanical contact, pressure gradients, etc.) or internal forces (e.g., pressure gradients). The ring 102 may be provided on the tubular member 100 such that the outer surface 104 is concave and the inner surface 106 is constant (e.g., smooth), as shown, for example, in fig. 2. Having a smooth inner surface 106 provides an interior cavity 108 (see fig. 2) through which fluid may pass without disrupting fluid dynamics. Having an outer surface 104 with a recess may allow the tubular member 100 to be more strongly anchored within the lumen of the patient. It should be appreciated that the depressions of the ring 102 may alternatively be positioned such that the depressions are formed in the inner surface 106 such that the outer surface 104 is smooth. In another alternative embodiment, the depressions formed by the ring 102 may be on the inner and outer surfaces 104, 106 (e.g., alternating, zoned, etc.).
The article 10 may be provided in a variety of configurations. In some embodiments, the article 10 includes multiple polymer layers. For example, the article 10 may be formed as a laminate of expanded polyethylene layers. The layers may be joined together via an adhesive, bonding process, or mechanical process. In some embodiments, the article 10 is shaped into a particular structure, such as the tubular member 100 described previously. The article 10 may be substantially free of adhesive. In these embodiments, the structure may be formed by bonding one portion of the article 10 to another portion of the article 10, or the article 10 may be provided in the shape of the structure (e.g., extruded, etc.).
Referring to fig. 3, an embodiment of a tubular member 100 is shown. The tubular member 100 includes a plurality of loops 102 (e.g., the second region 16 has been embossed to form a densified portion of the article 10). The tubular member 100 is shown in a bent configuration 160 wherein the tubular member 100 resists torsion. The provision of the rings 102 in the tubular member 100 helps enable the tubular member 100 to withstand short bend radii without twisting, which allows the internal cavity 108 to remain open and helps fluid flow through the internal cavity 108 without blocking or disrupting fluid dynamics. Because the tubular member 100 is not torqued, the durability of the tubular member 100 is greater because torqued generally defines a weak point (weakpot) on the implantable device over time. This is especially true when the implantable device is positioned within the patient's active cavity (which is subject to changes in shape, orientation, position, etc.).
Referring to fig. 4, a method 400 of forming an expanded polyethylene article is provided, according to some embodiments. The method of manufacture may include the method steps of providing an expanded polyethylene substrate 410, selectively densifying a portion 420 of the expanded polyethylene substrate, and optionally forming the expanded polyethylene substrate into an expanded polyethylene article 430.
With further reference to fig. 4, in providing an expanded polyethylene substrate 410, the polyethylene substrate has a first density. The expanded polyethylene substrate may include, but is not limited to, films, membranes, laminates, and the like. Providing the expanded polyethylene substrate 410 may further include positioning the expanded polyethylene substrate on a surface (e.g., surface 202 of fig. 5). The surface may comprise a mandrel.
Fig. 4 further, in selectively densifying a portion 420 of the expanded polyethylene substrate, a densified portion of the expanded polyethylene substrate (e.g., the second region 16 of the tubular member 100 of fig. 1) is formed. 1). Selective densification refers to densifying a portion of the expanded polyethylene substrate 420 such that the density of the portion in the expanded polyethylene substrate increases 420. In some embodiments, selectively densifying includes increasing density while maintaining voids 420 in the selectively densified portions of the expanded polyethylene substrate (e.g., not fully densified such that an open microstructure is retained). In some embodiments, selective densification includes an increase in density without retaining pores (e.g., complete densification such that no open microstructure is present). The portion 420 of the expanded polyethylene substrate that is not selectively densified is a porous portion that defines a portion that is not densified. Selective densification may be achieved through the thickness of the expanded polyethylene substrate 420 or along the length of the expanded polyethylene substrate 420. The densified portions of the expanded polyethylene substrate 420 may not be densified throughout the thickness of the expanded polyethylene substrate 420 such that at least some voids remain in the thickness of the expanded polyethylene substrate 420. In some embodiments, the undensified portion of the expanded polyethylene substrate 420 may be selectively masked such that the undensified portion remains undensified and porous. The densified portion of the expanded polyethylene substrate has a second density, and the second density may be greater than the first density. The densified portion of the expanded polyethylene substrate may be disposed adjacent to the portion of the expanded polyethylene substrate having the first density. Selective densification of a portion 420 of the expanded polyethylene substrate may be achieved by embossing. Selectively densifying a portion 420 of the expanded polyethylene substrate may further comprise applying heat to an outer surface of the expanded polyethylene substrate (e.g., outer surface 104 of tubular member 100 of fig. 1 and 2). Selectively densifying a portion 420 of the expanded polyethylene substrate may further comprise applying heat to an inner surface of the expanded polyethylene substrate (e.g., inner surface 106 of tubular member 100 of fig. 2). Applying heat to the expanded polyethylene-based material may further include placing the expanded polyethylene-based material on a mandrel and selectively heating portions of the mandrel (e.g., surface 202 of fig. 5).
With further reference to FIG. 4, the method 400 may optionally further include forming the expanded polyethylene substrate into an expanded polyethylene article 430. The expanded polyethylene article may comprise a tubular member. Shaping the expanded polyethylene into the tubular member may further comprise placing the tubular member on a mandrel. In some embodiments, the expanded polyethylene article may be formed by bonding one portion of the article to another portion of the article, or the article may be provided in the shape of the structure (e.g., extruded, etc.).
Fig. 5 illustrates an embossed article 220 of expanded polyethylene manufactured by the method of fig. 4, according to some embodiments. Fig. 5 includes providing an expanded polyethylene substrate 200 (e.g., film, laminate, etc.). The expanded polyethylene substrate 200 may be a tubular member (e.g., the tubular member 100 of fig. 1). The expanded polyethylene substrate 200 may have an outer surface 206 and an inner surface 208 (e.g., an inner cavity). The expanded polyethylene substrate 200 may be positioned on a surface 202 (e.g., on a mandrel) for further processing of the expanded polyethylene substrate 200. When positioned on surface 202, expanded polyethylene substrate 200 has a first density. The first density may be substantially uniform throughout the expanded polyethylene substrate 200, or a portion of the expanded polyethylene substrate 200 may have the first density. Once the expanded polyethylene substrate 200 is provided, the expanded polyethylene substrate 200 may be selectively densified by positioning the expanded polyethylene substrate 200 with the surface 202. The selective densification may include embossing. The embossing may occur via an external device (not shown; e.g., a soldering iron, a heating pestle, ultrasonic bonding, etc.), or the embossing may occur via the surface 202 (e.g., the mandrel may be heated, etc.). The outer surface 206 and/or the inner surface 208 may be selectively densified via embossing by an external device. The inner surface 208 may be selectively densified via imprinting of the surface 202.
In some embodiments, embossing, or selective densification, of the polyethylene substrate 200 may be achieved via ultrasonic energy. Ultrasonic energy may be applied to the outer surface 206 and/or the inner surface 208 of the polyethylene substrate 200 (e.g., using a mandrel). Ultrasonic energy may be applied using a rotary ultrasonic bonding unit comprising an anvil assembly. The anvil may include a pattern (e.g., circumferential ring) that may be imprinted onto the polyethylene substrate 200. The use of ultrasonic energy may allow the polyethylene substrate 200 to have more discrete density and pore differences between the imprinted and unembossed portions of the polyethylene substrate 200. This may be because the unembossed portions are less affected by the ultrasonic energy than the applied heat. This may allow the unembossed portion to better retain its density and porosity.
As the expanded polyethylene substrate 200 is embossed, the embossed portions densify such that they have a second density that is greater than the first density. Embossing may be accomplished in multiple steps such that the expanded polyethylene substrate 200 has both embossed portions 210 and unembossed portions 212. The embossing may be accomplished along the entire expanded polyethylene substrate 200, thereby creating an embossed article 220. It should also be appreciated that as the expanded polyethylene substrate 200 is embossed, the embossed configuration (e.g., pattern) may result in a shortening of the expanded polyethylene substrate 200. For example, fig. 4 shows an expanded polyethylene substrate 200 provided as an expanded polyethylene 230 tubular member embossed on an outer surface 206 to include a circumferential ring 204. When the circumferential ring 204 is embossed into the outer surface 206 of the expanded polyethylene 230 tubular member, the longitudinal length of the expanded polyethylene tubular member is shortened. The longitudinal length may be defined along the longitudinal axis L of the expanded polyethylene tubular member. The expanded polyethylene substrate 200 is provided in a first longitudinal length L1. When the embossed portion 210 is formed on a portion of the expanded polyethylene substrate 200, the expanded polyethylene substrate 200 has a middle longitudinal length LI. The intermediate longitudinal length LI is shorter than the first longitudinal length L1. When the embossed portion 210 is formed to the extent of the entire expanded polyethylene substrate 200, thereby producing an embossed tubular article 220, the embossed tubular article 220 has a second longitudinal length L2. The second length L2 is shorter than the intermediate length LI. In some embodiments, the length variation between the first longitudinal length L1 and the second longitudinal length L2 is small.
It should also be appreciated that the densification or imprinting process may or may not densify the expanded polyethylene substrate 200 throughout the thickness of the imprinted portion 210 of the expanded polyethylene substrate 200. For example, the expanded polyethylene substrate 200 may be densified only in a portion of the thickness of the expanded polyethylene substrate 200 such that there is a portion of the thickness that is not embossed (e.g., the inner surface 208 of the expanded polyethylene 230 tubular member). The portion of the thickness that is not embossed may substantially retain the first density (e.g., on the inner surface 208). Thus, with the densified portions positioned on the outer surface 206, the density at the embossed portions 210 has a continuous density range throughout the thickness of the expanded polyethylene substrate 200 at the embossed portions 210 when the cross-section of the expanded polyethylene substrate 200 is viewed. Accordingly, the inner surface 208 may substantially retain its porosity and fluid dynamics and/or hemodynamics by substantially retaining the first density.
Embossing or selective densification of the expanded polyethylene substrate 200 may be achieved by heating the expanded polyethylene substrate 200 using a tool at about the melting temperature of the expanded polyethylene substrate 200 or at about 110 ℃ to about 180 ℃. For example, the expanded polyethylene substrate 200 may be selectively heated to a temperature of from about 110 ℃ to about 120 ℃, from about 120 ℃ to about 130 ℃, from about 130 ℃ to about 140 ℃, from about 140 ℃ to about 150 ℃, from about 150 ℃ to about 160 ℃, from about 160 ℃ to about 170 ℃, and from about 170 ℃ to about 180 ℃.
Referring to fig. 6, a method 600 of forming an expanded polyethylene article is provided, according to some embodiments. The method of manufacture may include the method steps of providing an expanded polyethylene substrate 610, compressing the expanded polyethylene substrate into a compressed state 620, selectively densifying a portion of the expanded polyethylene substrate 630, releasing 640 the expanded polyethylene substrate from the compressed state, and optionally shaping the expanded polyethylene substrate into an expanded polyethylene article 650.
With further reference to fig. 6, in providing an expanded polyethylene substrate 610, the expanded polyethylene substrate has a first density. The expanded polyethylene substrate may include, but is not limited to, films, membranes, laminates, and the like. The expanded polyethylene substrate may include a tubular member (e.g., expanded polyethylene tubular member 300 of fig. 7). Providing the expanded polyethylene substrate 610 may further include disposing the expanded polyethylene substrate on a surface. The surface may include a mandrel (e.g., mandrel 302 of fig. 7).
With further reference to fig. 6, compressing the expanded polyethylene substrate into a compressed state 620 may be performed in a longitudinal direction and/or a lateral direction such that the expanded polyethylene substrate is in a longitudinal and/or lateral compressed state.
With further reference to fig. 6, selectively densifying a portion 630 of the expanded polyethylene substrate may be accomplished while the expanded polyethylene substrate is in a longitudinally and/or laterally compressed state, thereby forming a densified portion of the expanded polyethylene substrate (e.g., densified portion 306 of fig. 7). The densified portion includes a second density, and the second density may be greater than the first density. The densified portion of the expanded polyethylene substrate may be disposed adjacent to an undensified portion of the expanded polyethylene substrate having a first density (e.g., undensified portion 308 of fig. 7). Selective densification of a portion 630 of the expanded polyethylene substrate may be achieved by embossing. Selectively densifying a portion 630 of the expanded polyethylene substrate may further comprise applying heat to an outer surface of the expanded polyethylene substrate (e.g., outer surface 312 of fig. 7). Selectively densifying a portion 630 of the expanded polyethylene substrate may further comprise applying heat to an inner surface of the expanded polyethylene substrate (e.g., inner surface 314 of fig. 7). Applying heat 630 to the expanded polyethylene base material may further include placing the expanded polyethylene base material on a mandrel and selectively heating portions of the mandrel.
With further reference to FIG. 6, releasing 640 the expanded polyethylene substrate from the compressed state comprises releasing 640 the expanded polyethylene substrate from the longitudinal and/or lateral compressed state. The method 600 may additionally include forming the expanded polyethylene substrate into an expanded polyethylene article 650. The expanded polyethylene article may comprise a tubular member. Shaping the expanded polyethylene into the tubular member may further comprise placing the tubular member on a mandrel.
Further, fig. 7 is an expanded polyethylene embossed article 10 made by the method of fig. 6, according to some embodiments. In some embodiments, the embossed article 320 may be provided to have a stock length. This may be accomplished via a method of manufacturing the article 10. The method of making the article may be substantially similar to the method shown in fig. 6. For example, the method includes providing an expanded polyethylene substrate having a first density, such as a tubular member 300, the tubular member 300 being disposed on a surface 302 (e.g., mandrel 302). The expanded polyethylene substrate is not limited to tubular member 300 and may include, but is not limited to, a flat member, or other geometric shape. The expanded polyethylene substrate may be provided in an original length X1. Tubular member 300 includes an outer surface 312 and an inner surface 314 (e.g., lumen). Once the tubular member 300 is positioned, the tubular member 300 is compressed in a longitudinal or lateral direction into a compressed state 304 (e.g., not compressed throughout the thickness of the tubular member 300). In this embodiment, the compressed state 304 is defined in a longitudinal direction defined by the longitudinal axis L of the tubular member 300. The compressed state 304 may have a compressed length XC that is less than the original length X1. While tubular member 300 remains in compressed state 304 (e.g., tubular member 300 remains in longitudinally compressed state 304), tubular member 300 is selectively densified, forming densified portion 306. The densified portion 306 may be adjacent to the undensified portion 308. The densified portion 306 of the tubular member 300 has a second density that is greater than the first density of the tubular member 300 prior to densification. Selective densification may be accomplished via imprinting. Similar to the previous discussion, the stamping process may or may not densify tubular member 300 throughout the thickness of tubular member 300 at densified portion 306. For example, tubular member 300 may be densified only in a portion of tubular member 300 (e.g., outer surface 312 of tubular member 300) such that there is a portion of the thickness of tubular member 300 that is undensified (e.g., inner surface 314 of tubular member 300). The unembossed portion of the tubular member thickness may substantially retain a first density (e.g., on the inner surface of tubular member 300). Thus, with the densified portions positioned on the outer surface 312 of the tubular member 300, when the cross-section of the tubular member 300 is viewed, the density at the densified portions 306 is a continuous range of densities throughout the thickness of the tubular member 300 at the densified portions 306. Thus, the inner surface of the tubular member may substantially retain its porosity and fluid dynamics and/or hemodynamics. The tubular member 300 may be embossed or densified into various patterns including, but not limited to, rings 310. This results in a densified tubular member 320.
After selectively densifying the tubular member 300, the tubular member 300 is released from the compressed state 304, during which densification the tubular member 300 remains in the compressed state. As seen in fig. 7, when tubular member 300 is released from compressed state 304, densified tubular member 320 does not return to its original length X1. In some embodiments, the shortened length (or width) X2 of the densified tubular member 320 may be the result of the tubular member 300 being stamped in the compressed state 304. In addition, the shortened length (or width) X2 may be the result of an embossing or densification step. Regardless, the stamping of tubular member 300 in compressed state 304 helps to expand the reserve length (storedlength) within the polyethylene substrate. By applying a force at either end of densified tubular member 320, densified tubular member 320 can expand, releasing the reserve length and producing an expanded densified tubular member 330. The expanded densified tubular member 330 has an expanded length (or width) X3. The inflated length (width) X3 may comprise the full reserve length or a portion of the reserve length. In embodiments in which the entire reserve length is included in the expanded length (or width) X3, the expanded length (or width) X3 may be substantially the same as the original length X1. In other embodiments, the expanded length (or width) X3 may be less than the original length X1.
In some embodiments, the expanded polyethylene substrate is not provided as a tubular member 300, but is formed into a tubular member. This may occur before or after the imprinting/densification process described herein. For example, the expanded polyethylene substrate may be formed into a tubular member and then placed on a mandrel for densification, similar to the densification process shown in fig. 7. The expanded polyethylene substrate may be formed into a tubular substrate using any suitable method, including extrusion, bonding, adhesion, joining, and the like. In other embodiments, the tubular member is formed after embossing/densifying the expanded polyethylene substrate, such as by bonding, adhering, or otherwise joining the ends of the embossed expanded polyethylene substrate to one another.
In some embodiments, embossing/densifying the expanded polyethylene substrate includes selectively applying heat to an outer surface of the expanded polyethylene substrate. In some embodiments, the densification may occur at a temperature above the melting temperature of the expanded polyethylene substrate. In other embodiments, if an adhesive is present, the densification may occur at the melting temperature of the adhesive. In some embodiments, the expanded polyethylene substrate is a tubular member 300. Heat may be applied via a heating element (such as a soldering iron, a hot press, a heated tool element, etc.). Heat is applied to an outer surface (e.g., outer surface 312 of tubular member 300) to maintain the structural features of the inner surface (e.g., inner surface of tubular member 300). By maintaining the inner surface of the expanded polyethylene substrate, properties and functionality can be preserved. For example, the outer surface may have densified loops (e.g., loops 310) for structural support (e.g., formed by densification), while the inner surface substantially retains its selected structural qualities for, e.g., hemodynamics, cell adhesion, texture, and the like. It will be appreciated that the reverse configuration may be practiced where the inner surface may be modified by densification and the outer surface may substantially retain the structure or other qualities upon which the expanded polyethylene substrate is selected. In other embodiments, both the inner and outer surfaces may be modified to facilitate specific features for the inner or outer surfaces, or for the embossed article 320 defined by the expanded polyethylene substrate (e.g., further resistance to radial collapse, increased reserve length, increased bend radius, etc.). Heat may be applied to the expanded polyethylene base material using an assembly of about the expanded polyethylene base material melting temperature or at about 110 ℃ to about 180 ℃. For example, the expanded polyethylene substrate may be selectively heated to a temperature of from about 110 ℃ to about 120 ℃, from about 120 ℃ to about 130 ℃, from about 130 ℃ to about 140 ℃, from about 140 ℃ to about 150 ℃, from about 150 ℃ to about 160 ℃, from about 160 ℃ to about 170 ℃, and from about 170 ℃ to about 180 ℃. In some embodiments where the expanded polyethylene substrate is formed into a tubular member 300 prior to embossing/densification, the tubular member is placed on a mandrel 302. When a tubular member is positioned on the mandrel 302, the mandrel 302 may be selectively heated (e.g., in selected areas, including bars, patterns, etc.). This aids in the embossing/densification of the inner surface of tubular member 300.
While various materials may be implemented in accordance with the present disclosure, in one embodiment shown in fig. 3, a multi-layer expanded polyethylene substrate having an open, ventilated structure is provided without the use of an adhesive. The multi-layer expanded polyethylene substrate is rolled into a tubular member (e.g., tubular member 100). The multilayer expanded polyethylene substrate is then selectively densified using localized heating (e.g., via a soldering iron) at between about 110 ℃ and about 180 ℃ (e.g., at about 175 ℃). As shown in fig. 3, the selectively densified multilayer expanded polyethylene substrate exhibits high tortuosity without twisting of the tubular member 100.
Referring to fig. 5, in one non-limiting embodiment, a 6-ply rolled open, ventilated expanded polyethylene substrate (e.g., provided as expanded polyethylene substrate 200) may be provided. The multilayer expanded polyethylene substrate is selectively heated to densify portions of the multilayer expanded polyethylene substrate into densified rings (e.g., circumferential rings 204). The multilayer expanded polyethylene substrate is selectively heated using a soldering iron at a temperature between about 110 ℃ and about 180 ℃ (e.g., at about 150 ℃). Along the longitudinal length of the multilayer expanded polyethylene substrate, the densified rings are spaced about 2mm apart from each other. A multilayer expanded polyethylene substrate of about 9cm in length (e.g., disposed on a mandrel in a first length L1) may be provided prior to heating and having a length of about 7cm (e.g., a second length L2) when removed from the mandrel, as occurs in the case of compression (i.e., densification) when selectively heated to form a densified ring.
Referring to fig. 7, in one non-limiting embodiment, 6 layers of rolled open, ventilated expanded polyethylene substrate (e.g., provided as tubular member 300) may be provided and placed on a mandrel (e.g., surface 302). The multilayer expanded polyethylene substrate has a length of 9cm (e.g., original length X1). The multilayer expanded polyethylene substrate was kneaded to a length of 5.5 cm. The multilayer expanded polyethylene substrate is selectively heated to densify portions of the multilayer expanded polyethylene substrate into densified rings (e.g., compressed length XC). The multilayer expanded polyethylene substrate is selectively heated between about 110 ℃ and about 180 ℃ using a soldering iron. The multilayer expanded polyethylene substrate is removed from the mandrel. The multilayer expanded polyethylene substrate has a length of about 6cm (e.g., a shortened length X2) when the multilayer expanded polyethylene substrate is relaxed. The multilayer expanded polyethylene substrate includes a reserve length that allows the multilayer expanded polyethylene substrate to be stretched to a length (e.g., post-expansion length X3) of greater than 6 cm. In some embodiments, the expanded polyethylene substrate may return to a length of greater than 6cm either before stretching or after stretching.
Although specific embodiments are provided herein, it is understood that different arrangements and material properties may be selected and treated within the spirit of the present disclosure. Further, the detailed description provides temperatures, steps, and properties that may be varied while remaining within the spirit of the present disclosure.
The application has been described above generally and in connection with specific embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the application. Accordingly, it is intended that the embodiments cover the modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.